TY  - JOUR
A1  - Abouzar, Maryam H.
A1  - Ingebrandt, S.
A1  - Poghossian, Arshak
A1  - Zhang, Y.
A1  - Vu, X. T.
A1  - Moritz, W.
A1  - Schöning, Michael Josef
T1  - Nanoplate field-effect capacitive (bio-)chemical sensor array based on SOI structure
JF  - Procedia Chemistry. 1 (2009), H. 1
Y1  - 2009
SN  - 1876-6196
N1  - Proceedings of the Eurosensors XXIII conference ; Eurosensors 23
SP  - 670
EP  - 673
ER  - 
TY  - JOUR
A1  - Morais, Paulo V.
A1  - Gomes, Vanderley F., Jr.
A1  - Silva, Anielle C. A.
A1  - Dantas, Noelio O.
A1  - Schöning, Michael Josef
A1  - Siqueira, José R., Jr.
T1  - Nanofilm of ZnO nanocrystals/carbon nanotubes as biocompatible layer for enzymatic biosensors in capacitive field-effect devices
JF  - Journal of Materials Science
N2  - The incorporation of nanomaterials that are biocompatible with different types of biological compounds has allowed the development of a new generation of biosensors applied especially in the biomedical field. In particular, the integration of film-based nanomaterials employed in field-effect devices can be interesting to develop biosensors with enhanced properties. In this paper, we studied the fabrication of sensitive nanofilms combining ZnO nanocrystals and carbon nanotubes (CNTs), prepared by means of the layer-by-layer (LbL) technique, in a capacitive electrolyte-insulator-semiconductor (EIS) structure for detecting glucose and urea. The ZnO nanocrystals were incorporated in a polymeric matrix of poly(allylamine) hydrochloride (PAH), and arranged with multi-walled CNTs in a LbL PAH-ZnO/CNTs film architecture onto EIS chips. The electrochemical characterizations were performed by capacitance–voltage and constant capacitance measurements, while the morphology of the films was characterized by atomic force microscopy. The enzymes glucose oxidase and urease were immobilized on film’s surface for detection of glucose and urea, respectively. In order to obtain glucose and urea biosensors with optimized amount of sensitive films, we investigated the ideal number of bilayers for each detection system. The glucose biosensor showed better sensitivity and output signal for an LbL PAH-ZnO/CNTs nanofilm with 10 bilayers. On the other hand, the urea biosensor presented enhanced properties even for the first bilayer, exhibiting high sensitivity and output signal. The presence of the LbL PAH-ZnO/CNTs films led to biosensors with better sensitivity and enhanced response signal, demonstrating that the adequate use of nanostructured films is feasible for proof-of-concept biosensors with improved properties that may be employed for biomedical applications.
Y1  - 2017
U6  - http://dx.doi.org/10.1007/s10853-017-1369-y
SN  - 1573-4803
VL  - 52
IS  - 20
SP  - 12314
EP  - 12325
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Abouzar, Maryam H.
A1  - Razavi, A.
A1  - Bäcker, Matthias
A1  - Bijnens, N.
A1  - Williams, O. A.
A1  - Haenen, K.
A1  - Moritz, W.
A1  - Wagner, P.
A1  - Schöning, Michael Josef
T1  - Nanocrystalline-diamond thin films with high pH and penicillin sensitivity prepared on a capacitive Si–SiO2 structure
JF  - Electrochimica Acta. 54 (2009), H. 25
Y1  - 2009
SN  - 0013-4686
SP  - 5981
EP  - 5985
ER  - 
TY  - JOUR
A1  - Christiaens, P.
A1  - Abouzar, Maryam H.
A1  - Poghossian, Arshak
A1  - Wagner, Torsten
A1  - Bijnens, N.
A1  - Williams, O. A.
A1  - Daenen, M.
A1  - Haenen, K.
A1  - Schöning, Michael Josef
A1  - Wagner, P.
T1  - Nanocrystalline diamond-based field-effect capacitive pH sensor
JF  - Transducers '07 Eurosensors XXI : digest of technical papers ; the14th International Conference on Solid-State Sensors, Actuators and Microsystems, June 10-14, 2007, Lyon, France / Gilles Delapierre (Ed.)
Y1  - 2007
SN  - 1-4244-0841-5
N1  - Eurosensors 21, 2007, Lyon ; International Conference on Solid-State Sensors, Actuators and Microsystems 14, 2007, Lyon
SP  - 1891
EP  - 1894
PB  - IEEE
CY  - Piscataway
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Abouzar, Maryam H.
A1  - Christiaens, P.
A1  - Williams, O. A.
A1  - Haenen, K.
A1  - Wagner, P.
A1  - Schöning, Michael Josef
T1  - Nanocrystalline diamond-based field-effect (bio-)chemical sensor
JF  - 8. Dresdner Sensor-Symposium : Sensoren für Umwelt, Klima und Sicherheit, Biosensoren und Biosysteme, Sensoren und Sensorsysteme für die Prozesstechnik, Trends in der Sensortechnik, Materialentwicklung für die Sensorik; 8. Dresdner Sensor-Symposium, 10. - 12. Dezember 2007, Dresden / Gerald Gerlach ... (Hg.)
Y1  - 2007
SN  - 978-3-940046-45-1
N1  - Dresdner Sensor-Symposium <8, 2007, Dresden> ; Dresdner Beiträge zur Sensorik ; 29
SP  - 191
EP  - 194
PB  - TUDpress, Verl. der Wissenschaften
CY  - Dresden
ER  - 
TY  - JOUR
A1  - Schroth, P.
A1  - Schöning, Michael Josef
A1  - Schütz, S.
A1  - Steffen, A.
A1  - Weißbecker, B.
A1  - Hummel, Hans E.
A1  - Kordos, P.
A1  - Lüth, H.
T1  - Nachweis von organischen Duftstoffen durch Biosensoren auf der Basis von Insektenantennen
JF  - Gesellschaft Mess- und Automatisierungstechnik: Sensoren und Meßsysteme 2000 : Tagung Ludwigsburg, 13. und 14. März 2000 / VDI/VDE-Gesellschaft Meß- und Automatisierungstechnik
Y1  - 2000
SN  - 3-18-091530-7
N1  - VDI-Berichte; 1530
SP  - 107
EP  - 114
PB  - VDI-Verl.
CY  - Düsseldorf:
ER  - 
TY  - JOUR
A1  - Khaydukova, M. M.
A1  - Zadorozhnaya, O. A.
A1  - Kirsanov, D. O.
A1  - Iken, Heiko
A1  - Rolka, David
A1  - Schöning, Michael Josef
A1  - Babain, V. A.
A1  - Vlasov, Yu. G.
A1  - Legin, A. V.
T1  - Multivariate processing of atomic-force microscopy images for detection of the response of plasticized polymeric membranes
JF  - Russian journal of applied chemistry
N2  - The possibility of using the atomic-force microscopy as a method for detection of the analytical signal from plasticized polymeric sensor membranes was analyzed. The surfaces of cadmium-selective membranes based on two polymeric matrices were examined. The digital images were processed with multivariate image analysis techniques. A correlation was found between the surface profile of an ion-selective membrane and the concentration of the ion in solution.
Y1  - 2014
U6  - http://dx.doi.org/10.1134/S1070427214030112
SN  - 1608-3296 (E-Journal); 1070-4272 (Print)
VL  - 87
IS  - 3
SP  - 307
EP  - 314
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Karschuck, Tobias
A1  - Schmidt, Stefan
A1  - Achtsnicht, Stefan
A1  - Poghossian, Arshak
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
T1  - Multiplexing system for automated characterization of a capacitive field-effect sensor array
JF  - Physica Status Solidi A
N2  - In comparison to single-analyte devices, multiplexed systems for a multianalyte detection offer a reduced assay time and sample volume, low cost, and high throughput. Herein, a multiplexing platform for an automated quasi-simultaneous characterization of multiple (up to 16) capacitive field-effect sensors by the capacitive–voltage (C–V) and the constant-capacitance (ConCap) mode is presented. The sensors are mounted in a newly designed multicell arrangement with one common reference electrode and are electrically connected to the impedance analyzer via the base station. A Python script for the automated characterization of the sensors executes the user-defined measurement protocol. The developed multiplexing system is tested for pH measurements and the label-free detection of ligand-stabilized, charged gold nanoparticles.
KW  - Capacitive field-effect sensor
KW  - Gold nanoparticles
KW  - Label-free detection
KW  - Multicell
KW  - Multiplexing
Y1  - 2023
U6  - http://dx.doi.org/10.1002/pssa.202300265
SN  - 1862-6300 (Print)
SN  - 1862-6319 (Online)
N1  - Corresponding author: Michael Josef Schöning
VL  - 220
IS  - 22
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - THES
A1  - Achtsnicht, Stefan
T1  - Multiplex-Magnetdetektion von superparamagnetischen Beads zur Identifizierung von Trinkwasserkontaminationen
N2  - Die qualitative und quantitative Detektion von Zielsubstanzen innerhalb einer wässrigen Probe ist für viele Fragestellungen von Interesse, etwa bei der Detektion von Kontaminationen in Trinkwasser in Krisensituationen. Hierbei ist es nicht nur wichtig, dass Pathogene möglichst sensitiv detektiert werden können, sondern auch, dass die Analyse schnell erfolgt, um Betroffenen im Katastrophenfall zügig sicheres Trinkwasser zu Verfügung stellen zu können. Da bei einem solchen Szenario nicht von einer in der Nähe befindlichen funktionierenden Laborinfrastruktur ausgegangen werden kann, ist es wichtig, dass die Messung direkt vor Ort erfolgen kann. Im Rahmen dieser Arbeit wurde untersucht, ob eine derartige Schnellanalytik mithilfe von superparamagnetischen Beads (MBs) und der magnetischen Frequenzmischtechnik möglich ist. Dabei werden die MBs mit Hilfe von primären Antikörpern an die Zielsubstanz gebunden und mit sekundären Antikörpern an die Poren-Oberfläche eines Polyethylen-Filters fixiert (Sandwich-Immunoassay). So kann die Quantifizierung der Zielsubstanz auf eine magnetische Messung der immobilisierten MB-Marker zurückgeführt werden. Die magnetische Frequenzmischtechnik basiert auf der Anregung der Probe mit Magnetfeldern zweier verschiedener Frequenzen. Die durch die nichtlineare Magnetisierungsform der superparamagnetischen MBs entstehenden Mischfrequenzen werden typischerweise mithilfe einer zweistufigen Lock-in-Detektion analysiert (analoge Demodulation), die in einem Magnetreader als Handheldgerät realisiert wurde. Zusätzlich zu dieser Technik wurde das Prinzip der direkten Digitalisierung des gesamten Antwortsignals mit anschließender Fourier-Analyse der erzeugten Mischfrequenzen experimentell umgesetzt, um die Amplituden und Phasen mehrerer Mischfrequenzen simultan zu erfassen. Eine Möglichkeit zur Sensitivitätssteigerung ist die magnetische Aufkonzentration, indem vor der magnetischen Analyse eine Separation der MBs aus einem größeren Probenvolumen mittels magnetischem Feldgradienten durchgeführt wird. Zur Charakterisierung verschiedener kommerzieller MBs hinsichtlich ihrer magnetischen Separierbarkeit wurde ein Aufbau zur Messung ihrer magnetophoretischen Beweglichkeiten realisiert und ihre Geschwindigkeiten im Gradientenfeld mikroskopisch gemessen.Da eine Probe oftmals nicht nur auf eine einzige Zielsubstanz, sondern simultan auf mehrere verschiedene Pathogene hin untersucht werden soll, wurden verschiedene Ansätze entwickelt und getestet, die einen solchen multiparametrischen magnetischen Immunoassay ermöglichen. Einerseits wurde eine räumliche Separation der Bindungsbereiche für verschiedene Zielsubstanzen realisiert, die sequentiell ausgewertet werden können. Andererseits wurde die Unterscheidung von verschiedenen Zielsubstanzen anhand der Charakteristika der an sie gebundenen, verschieden funktionalisierten MB-Typen untersucht. Für eine solche Unterscheidung wurde zum einen die Anregefrequenz der magnetischen Frequenzmischtechnik während einer Messung variiert. Damit konnte gezeigt werden, dass sich verschiedene MB-Sorten anhand der Phase ihrer Frequenzmischsignale voneinander unterscheiden lassen. Weiterhin wurde gezeigt, dass sich der Signalverlauf einer binären Mischung zweier verschiedener MB-Typen als gradueller Übergang der Verläufe der beiden reinen MB-Lösungen ergibt. Eine weitere Analysemethode für einen multiparametrischen Immunoassay besteht darin, ein zusätzliches einstellbares statisches magnetisches Offsetfeld zu verwenden. Hierfür wurden mehrere Aufbauten auf Basis von Permanent- und Elektromagneten simuliert, konstruiert und charakterisiert. Mithilfe von Simulationen konnte gezeigt werden, dass eine auf diesem Verfahren beruhende Unterscheidung für MBs mit unterschiedlichen magnetischen Partikelmomenten möglich ist. Als direkte Anwendung des hier entwickelten Magnetreaders in Zusammenspiel mit der digitalen Demodulation wurde ein magnetischer Assay gegen die B-Untereinheit des Choleratoxins in Trinkwasser mit einem niedrigen Detektionslimit von 0,2 ng/ml demonstriert.
N2  - The qualitative and quantitative detection of target substances in an aqueous sample is of interest for many questions, for example in the detection of contaminations in drinking water in crisis situations. It is not only important that pathogens can be detected with highest possible sensitivity, but also that the analysis is carried out quickly so that safe drinking water can be provided in the event of a disaster. During such a scenario one cannot rely on a functioning laboratory infrastructure nearby. Therefore it is important that the measurement can be carried out directly on site. Within the scope of this work, it was investigated whether such a quick analysis can be performed using superparamagnetic beads (MBs) and the magnetic frequency mixing technique. The MBs are bound to the target substance with the aid of primary antibodies and fixed to the pore surfaces of a polyethylene filter with secondary antibodies (sandwich immunoassay). The quantification of the target substance can thus be traced back to a magnetic measurement of the immobilized MB markers. The magnetic frequency mixing technique is based on the excitation of the sample with magnetic fields of two different frequencies. The mixing frequencies generated due to the non-linear shape of the magnetization of the superparamagnetic MBs are typically analyzed using a two-stage Lock-in detection (analog demodulation), which was implemented in a magnetic reader as a handheld device. In addition to this technique, the principle of direct digitization of the entire response signal with subsequent Fourier analysis of the generated mixing frequencies was experimentally implemented in order to simultaneously record the amplitudes and phases of several mixing frequencies. One possibility for increasing the sensitivity is magnetic concentration. In that case, the MBs are separated from a larger sample volume by means of a magnetic field gradient before the magnetic analysis. To characterize various commercial MBs with regard to their magnetic separability, a setup for measuring their magnetophoretic mobility was implemented and their velocities in the gradient field were measured with an optical microscope.Often, a sample has to be examined not only for a single target substance, but for several different pathogens simultaneously. Various approaches have been developed and tested which enable such a multiparametric magnetic immunoassay. On the one hand, a spatial separation of the binding areas for different target substances was realized, which can be evaluated sequentially. On the other hand, a distinction among different target substances based on the magnetic characteristics of their attached different MB types was examined. For this discrimination, the excitation frequency of the magnetic frequency mixing technology was varied during measurement. It is shown that different MB types can be distinguished from one another based on the phase of their frequency mixing signals. The signal curve of a binary mixture of two different MB types is obtained as a gradual transition of the curves of the two pure MB solutions. Another method of analysis for a multiparametric immunoassay is based on an additional adjustable static magnetic offset field. For this purpose, several setups based on permanent magnets and electromagnets were simulated, designed and characterized. The simulations show that a distinction based on this method is possible for MBs with different magnetic particle moments. As a direct application of the developed magnetic reader in conjunction with digital demodulation, a magnetic assay against the B subunit of cholera toxin in drinking water was demonstrated, and a low detection limit of 0.2 ng/ml was achieved.
KW  - Choleratoxin B
KW  - Trinkwassersicherheit
KW  - cholera toxin B
KW  - drinking water safety
KW  - magnetic frequency mixing technique
Y1  - 2020
U6  - http://dx.doi.org/10.18154/RWTH-2020-12052
N1  - Dissertation, RWTH Aachen University, 2020
ER  - 
TY  - JOUR
A1  - Pourshahidi, Ali Mohammad
A1  - Achtsnicht, Stefan
A1  - Nambipareechee, Mrinal Murali
A1  - Offenhäusser, Andreas
A1  - Krause, Hans-Joachim
T1  - Multiplex detection of magnetic beads using offset field dependent frequency mixing magnetic detection
JF  - Sensors
N2  - Magnetic immunoassays employing Frequency Mixing Magnetic Detection (FMMD) have recently become increasingly popular for quantitative detection of various analytes. Simultaneous analysis of a sample for two or more targets is desirable in order to reduce the sample amount, save consumables, and save time. We show that different types of magnetic beads can be distinguished according to their frequency mixing response to a two-frequency magnetic excitation at different static magnetic offset fields. We recorded the offset field dependent FMMD response of two different particle types at frequencies ƒ₁ + n⋅ƒ₂, n = 1, 2, 3, 4 with ƒ₁ = 30.8 kHz and ƒ₂ = 63 Hz. Their signals were clearly distinguishable by the locations of the extremes and zeros of their responses. Binary mixtures of the two particle types were prepared with different mixing ratios. The mixture samples were analyzed by determining the best linear combination of the two pure constituents that best resembled the measured signals of the mixtures. Using a quadratic programming algorithm, the mixing ratios could be determined with an accuracy of greater than 14%. If each particle type is functionalized with a different antibody, multiplex detection of two different analytes becomes feasible.
KW  - colorization
KW  - multiplex detection
KW  - frequency mixing magnetic detection
KW  - magnetic nanoparticles
Y1  - 2021
U6  - http://dx.doi.org/10.3390/s21175859
SN  - 1424-8220
N1  - This article belongs to the Special Issue "Advanced Nanomaterial-Based Sensors for Biomedical Applications"
VL  - 21
IS  - 17
PB  - MDPI
CY  - Basel
ER  -